Elk Island National Park of Canada

Bison Disease Management

History

The two diseases of principle concern to bison in Canada are bovine tuberculosis and brucellosis (TB). Several thousand plains bison have been tested for TB in Elk Island and during their entire stay in the Park, TB has never been documented. Despite this 90-year history of disease free status, Elk Island will always test for the presence of the disease in all bison that leave the Park.

Brucellosis, however, was found in the herd during the late l940s and by the mid-1950s had begun to have an impact on calving rates and herd health. Throughout this period and into the early 1960s a test and slaughter program was in place. It was not until the mid-1960s that the combination of vaccinations and slaughters took effect. By January 1969, there were only two suspected cases of brucellosis, and by 1972, the park was declared free of brucellosis. As with TB, the Park continues to test for brucellosis each year. All surplus bison are certified free of both diseases.

Agriculture & Agri-Food Canada has accorded Elk Island National Park with equivalent status to a game farm's Negative Herd Status. This status assures all producers and other government agencies that the animals they obtain from Elk Island have come from a herd with negative status.

Present status and protocols

During the summer of 1996, Park staff observed several young bulls with severe diarrhoea and in an emaciated condition. These animals were submitted to the Provincial Veterinary Lab for necropsy and a disease known as Bovine Viral Diarrhoea (BVD) was identified. As the name implies, this is a virus that affects cattle, or Bovids, and is found in cattle around the world. It is suspected that cattle adjacent to Elk Island are the source of the disease but this has not been confirmed. Transmission is thought to be through infected body fluids.

Testing of the entire captured component of the Park herd (561 of 665) was done during December 1996. The results of this intense testing program indicate that 47% of the plains bison had been exposed to the disease and developed antibodies as a result. Only one animal in the herd was confirmed to be actually carrying the disease. This animal was euthanased and submitted to the lab for subsequent necropsy. In addition to testing the herd for the presence of the disease, all bison that came through the facility were vaccinated against the disease. As an added precaution, all bison were vaccinated with a CattleMaster 4 vaccine. This vaccine is used to protect livestock from Infectious Bovine Rhinotracheitis (IBR); Parainfluenza 3 (P13); Bovine Respiratory Syncytial Virus (BRSV) and Blackleg. A BVD killed vaccine is being used in all potentially pregnant animals and suckling calves. A modified live virus is being used in all other animals. This vaccination program is now an annual component of bison management in Elk Island National Park.

The prevalence of BVD in bison across North America is not well understood. It has recently been found in bison on farms and in the wild in Saskatchewan, and it has been found in free-roaming elk in southern Alberta. The disease is fairly wide-spread in the cattle industry.

During the early 1990s, pink eye (Infectious bovine keratoconjunctivitis) began to appear in the bison in Elk Island. This disease is spread during the spring and summer by flies with the primary effect of partial or complete blindness in one or both eyes. The animal must be physically restrained to treat the damage, and this should be done during the spring when the infections are most prevalent. Since this is not feasible, it is not possible to treat the bison against pinkeye.